Geared electric motor



June 13, 1933'.

w. R. UGGLA GEARED ELECTRIC MOTOR Filed April 16, 1930 4 Sheets-Sheet 1June 13, 1933. w. R. UGGLA 1,913,523

GEARED ELECTRIC MOTOR June 13, 1933. w UGGLA 1,913,523

GEARED ELECTRIC MO'IIOR Filed April 16, 1930 v 4 Sheets-Sheet 15 Jude13, 1933.

W. R. UGGLA GEARED ELECTRIC MOTOR Filed April 16, 1930 4 Sheets-Sheet 4whgggg 25%;

4;, ATTORNEY Patented J une 13, 1933 UNITED STATES PATENT OFFICE WILHELM'nonnnr UGGLA, or mossy, swnnniz, ASSIGNOR T0 ALLMKNNA svnns mELEKTRISKA .AKTIEBOLAGET, or VASTERAS, swnmm, A conrone'rrou or swnnmr'GEABED ELECTRIC MOTOR Application filed April 18, 1930. Serial No.444,703.

The type 'of geared electric motors previously known is built on theprinciple that a standard type electric motor is provided with areduction gear fixed thereon, for instance by substituting a reductiongear devicefor one of the end shield bearing brackets of the motor.

In electric motors of the geared type the size of the reduction gearrelatively to the motor sizeincreases on increasing motor capacity. Insmaller geared motors the dimensions of the reduction gearare smallenough to permit the casing of the gear to be. directlv secured to themotor casin for instance by bolts or the like, that is, the

gear casing can be carried by the motor casing. In larger motors of thistype, however, the reduction gear is too heavy to permit suchoverhanging. In such cases it has, therefore, been necessary to supportthe gear casing in a suitable manner, for instance by the provision offeet ext-ending from said casing. This arrangement involves, however,several disadvantages. For instance, it is diilicult to attain a correctalignment of said. additional-feet and the feet of the motor casing,there being required diflicult adjustments in mounting the motor and thegear. llloreovenbending stresses are created even if the bed plate orfoundatlon is Fig. 2 is a top plan View;

Fig. 3 is a cross-sectional view taken on the line 3-3 of Fig. 2; I

Fig. 4 is. a cross-sectional view taken on the line 4-4 of Fig. 1';

Fig. 5 illustrates in its left half an end view of the cover of theelectric part of the unit and in its right half a section on the line 55in Fig. 3;

Fig, 6 is a section on an enlarged'scale along the line 66 in Fig. 3showing the collector-ring device of the electric apart of the unit Fig.7 is a section on the line 7-'7 in Fig. 3showing especially the gearpart of the unit containing an oil relay;

Fig. 8 shows a section on the line 88 in Fig. 9' which in turn is asection on the line 9- 9 in Fig. 8, both figures illustrating ayieldable gear wheel of the gear;

Fig. 10 is a horizontal section on an enlarged scale showing the oilpacking device between the gear part and the electric pa of the unit;

Fig. 11 is a horizontal section on an enlarged scale of acircuit-breaker with no- 4 oil release on the line 1111 in Fig. 7;

Fig. 12 is a wiring diagram of the electric connections of. the unit;and

Figs. 13 and 14 show a modified embodiment of a detail of the gear partof the unit.

In the following'the different parts of my improved geared electricmotor unit will be described in detail.

I. GENERAL CONSTRUCTION With reference especially to Figs. 1 and 2' myimproved geared. electric motor unit comprises a casing or frame 10, 11common to the whole unit, that is, to the electric part as well as tothe gear part. The lower part 11 of the casing is provided with fourstrong feet 12, one at each corner of the bottom of the casing. Thisconstruction into two halves 10, 11 secured together in known manner asfor instance by screw bolts 13 and nuts 14. It is evident that thisdivision of the easing into a top part 10 and a bottom part 11 involvesseveral advantages with'regard to inspection and repair which is easilyeffected after the removal of thetop part 10, and also with regard tothe mounting and dismantling of the differ- The ent parts of the unit aswill be further de-,

scribed. Reference character 15 designates a cover for an inspectionopening in the top part 10 of the casing covering the gear. A bearingshield 16 is secured to the one end of the casing in a suitable mannerand is divided into two halves corresponding to the halves of the casingproper, said parts of the shield 16 being secured together by screwbolts 13 and nutsl l. In this bearing shield the driving shaft isjournalled in a manner described in the following. A separate undividedcap 17 surrounds the collector-ring device of the electric part ofin thefollowing.

II. THE Ernormo Pam The electric part of the unit is shown in section inFigs. 3 and 4. It comprises a stator 21 and a rotor 22, the latter fixedlo the motor shaft 23 in any suitable manner. At one end (the left handend in Figs. 3 and 4) the shaft 23 is journalled in a bearing, forinstance a ball bearing 24 secured to the bearing shield 16. The shaft23 extends from said bearing to the collector-ring device which,consequently, is associated with the overhung portion of the shaft. Atthe other end (the right-hand end in Figs. 3 and 4) the shaft 2 isjournalled in a hearing, for instance a ball bearing 25. arranged in atransverse partition 26 dividing the common casing of the unit into twocompartments, one of which houses the electric part and the other onethe gear part of the unit.

T/zc stator The stator plates and their windings are designated as awhole by reference character 21 and are arranged in a separateannular-casing or cage 27 held in position by means of flanges 28 extendingfrom the common casing and secured by a screw pin 29 (see. Fig. Whenmounting the stator, it is simply placed in the bottom half 11 of thecasing so as to rest on the flanges 28 and it is then secured inposition by the pin 2?). Thus, the stator 21 is readily accessible forinspection and repair, it being only necessary to remove the top half ofthe casing whereupon the stator can be lifted out as a whole after therotor has been taken out from the unit in a manner to be described inthe following, or the stator and the rotor can be removed together.Hence, it is not necessary to displace the unit from its bed, which isvery advantageous as such displacement usually is troublesomeand-,.moreover requires detachment of the underground cables. andreadjustment of the unit.

Electric current is supplied to the stator windings by means of cables80 extending from a terminal plate 31 in the casing at one sidethereof.' This plate 31 may be covered by an ordinary protecting coveror a cable box 32 may be provided, the latter arrangement being shown inFig. 4.

(b). The rotor As above stated the electric rotor 22 isfixed on theshaft 23. 'At the outer surface of the bearing box 33 a groove 34 (seeFig. .10) is provided containing a wick soaked with soft soap serving aspacking means against oil leakage axially and outwardly around thebearing box. However, this arrangementis only a precautionary measure,other means being provided to prevent leakage. as will he described inthe following.

Electric current is supplied to the rotor by cables extending from thecable box 36 (see also Fig. 1) to the collector-ring device through abore in the bearing shield 16 arranged at the; plane of division toterminals 37 of the brush holders 38 (see Fig. 6). From thecollector-rings 39 cables -10 extend through a bore? 41 in the shaft 23(see especially Fig. 4) to the rotor windings 22.

(0);.(700Z2'12g of the electric part I The cooling of the electric partof-the unit is effected by axial ventilation by a fan 42 (see Figs. 3and 4) provided between the electric part and the gear part. The fan 42is fixed on hub 43 by screws 44. which hub 43 is secured to the shaft 23by means of radially extending screws 45 and a key 46. Air is drawn inthrough an inlet opening 47 formed in the casing and exhausted throughan outlet opening 48. As seen especially in the right half of Fig. 5 theannular casing 27 of the stator is provided with a plurality of coolingchannels 49 extending axially of the casing and open at theirboth ends.These channels are traversed by the main part of the air (the Wholequantity of cooling air except that passing through the rotor), thuseffecting a good cooling action.

However, in some cases it may be of advantage to provide for an indirectcooling of the electric part, that is, to provide a cool-- ing system inwhich the coolin air does not directly meet the windings of the electricpart, this being of importance especially when the unit is erected industy localities. The embodiment shown in the drawings is provided withsuch a cooling system. As seen in Figs. 3 and 4 end covers 50 areprovided at opposite sides of the annular stator cage 27, said endcovers 50 and annular cage 27 entirely enclosing the electric part.These end covers 50 are divided into two halves corresponding to the twohalves of the principal casing, said halves being secured together inknown manner. At their outer surface the end covers 50 are provided witha plurality of radially extending cooling ribs or fins 51 (see the lefthalf of Fig. 5) and at their inner surface with a plurality ofprojections or studs 52 (see Figs. 3 and 4) for the purpose ofincreasing thecooling surfaces. In this system of indirect cooling theair is drawn in through the inlet opening 47, sweeps past the left endcover 50 (Figs. 3 and 4), flows through the cooling channels 49 in thestator cage 27, sweeps past the right end cover 50 and exhausts throughthe outlet opening 48. The cables 30 pass through a bushing 53 at'theplane of division of one end of the cover 50. In such cooling system theelectric cables will be in the path of the whole quantity of air, and ifthe air is impure and injurious to the cables; the latter maybeconstructed in any suitable manner so as to resist the destruc tiveaction of the impure air.

For balancing purposes a hub 54 similar to the fan hub 43 is secured tothe shaft 2: at the opposite side of the electric part symmetrically toits central vertical plane, said hubs 48 and 54 being provided withcavities 55 in which lead or the like may be placed so as to balance therotor in a correct manner.

In prior constructions the gear part was unsuitaby heated by theelectric part, the portion of the gear adjacent to the electric partgrowing considerably warmer than the opposite end of the gear. Ofcourse, this difference in temperature between the ends of the gear isunsuitable for a proper tooth engagement as the gear will expanddifferently. In my geared electric motor unit this drawback iseliminated by the gear part being separated from the electric part bymeans of the partition 26 above referred to. I have found by thisconstruction that the temperature of the gear is maintained uni- III.

(a). General construction THE GEAR PART As already stated, the casing ofthe gear part of my improved unit is made integral with that of theelectric part. The part of the casing which houses the gear is stayed bya plurality of longitudinal flanges 56 (see Fig. 7) extending axiallyinto partition 26 and between the end wall 57 of the casing.

The gear part of my unit is of the socalled double type, that is to saythe motor shaft 23 and the driven shaft 19 are arranged co-axially inrelation to each other, having two identical series of gear wheelsarranged thcrebetween, one on each side of said shafts.

Secured at the end of the motor shaft 23 adjacent to the gear part is apinion 58. In engagement with said pinion on each side thereof are twogear wheels 59, each secured to an intermediate shaft 60, saidshafts,being each journalled in two bearings, for instance ball bearings61, 62, one 61 arranged in the end wall 57 of the casing and the otherin a partition wall 63 arranged transversely of the toothed gearingcasing. Secured to each of said intermediate shafts 60, intermediate tosaid bearings 61, 62, is a pinion 64, both said pinions engaging acommon gear wheel 65 secured to the driven shaft 19. The shaft 19 isjournalled in the same manner as the intermediate shafts 60, forinstance by means of ball bearings 66, 67. The construction of the gearwill especially be clear from Figs. 4 and 7.

All the pinions and gear wheels are of the double herring bone type,each consisting of two halves placed close to one another and havingobliquely directed teeth.

The bearings 61 and 62 of the intermedi ate shafts 60 are mounted inbearing races 68 and 69, respectively. When dismantling the unit, it isimpossible to lift the intermediate shafts 60 when the pinions 64 andthe yieldable gear wheels 59 thereon are in engagement with the gearwheel 65 and the pinion 58 on the driven and the driving shaft,respectively. In order to disengage the gear wheels of. the bearing, thebearing races 68 and 69 are first removed, a suflicient play then beinghad for displacing the intermediate shafts 60 laterally so as to bringthe gear wheels out of engagement with each other.

In order to maintain the gear wheelsand the shafts of the gear in theirposition and to prevent their axial displacement, rings are providedbetween the bearings and the wheels and plates 71 are secured to theends of the shafts by bolts, not shown.

In geared electric motors hitherto known the shaft of the slowestrunning gear wheel (35 has been journalled only at one end thereof, thatis, the wheel is mounted on an overhanging portion of the shaft. In thisconstruction the driven shalt could not be exactly guided, nor couldunexpeeted loads, easily oceurring on aceount of incorrect mounting,settlihgs in l-llt.,tl.tljtlt.(l ll3 bearings, ete., be taken up. In myimproved unit these disiulvantages are eliminated by the slowest runningshaft 19 being journalled at both sides of the gear wheel (35, thusensuring a more etl'ective journalliug of the shaft.

(7)). The yieZJab/e (m' wheels The gear wheels 59 in engagement withthedriving pinion 58 are provided with yieldable tooth rims, asespecially shown in Figs. 8 amt t). The. hub of the gear wheel 55) hasan inner part 72 by which the wheel is secured on the intermediateshal't so and an outer part T3, the latter being provided with recesses74 in which spiral springs 75 are located. ()tt'sets 76 between twoadjacent recesses torm ulna-meats against whieh the springs 75 bear. Byproviding the springs in the recesses, they may be given a certaininitial tension. Ar 'anged |wriphera|lv on the outer part 73 of the hubis a toothed rim 77 divided into two halves connected by screws 78, saidserews also securing plates 79 located in guiding grooves Ht) betweenthe two halves of the .rim 7? and extending into grooves 81 between theotl'sets 7e and thus forming abutments for the. springs 75. The twohalves of the rim are eaeh provided with teeth of shape so as to formtogether a V-shaped tooth-profile. It is evident that in operation ofthe gear the power is trans- "mitted from the driving pinion 5b to theyieldable. toothed rims 77 and therefrom throughgtlie plates 79, thehelical springs 7!) and the otl'sets'i'ti to the hub 73). T2 mat theintermediate shafts (it).

In order to etleet lubrication of the helical springs 75 in theyieldable gear wheels 55), annular grooves 82 are. provided in the hubof the wheel from which channels 83 lead o the central recesses 74 inthe hub.

In prior constructions the slowest running gear wheel (35 was, as statedabove, secured in overhung arrangement on the driven shal't l9, whereasthe yieldable. gear wheels 59 were journalled in hearings on both sides.In the eonstruetion shown the arrangement is the contrary, the drivengear wheel 5 being. as already stated, jgmrnalled at both sides, withthe :ulvantages mentioned above,

whereas the yielclable gear wheels 59 are secured in overhungarrangement on the intermediate shafts 60. However, this manner ofjournalling the intermediate shafts 60 does not involve anydisadvantage, as the yieldable gear wheels 59 are not subjected to anyunexpected or umamtrollable forces. Further, it has proved that byjonrnalling the different shat'ts in the manner described and shown the:ulditional advantage is gained that the. yielding ot' the intermediateshafts will be smaller than would be the case if said shafts werejournalled in the old manner.

(0) (NZ packing means In a gear it is generally ditlieult to prevent oilleakage around the driving and driven shat'ts. It has not provedsuitable to apply the oil splashing principle. to the driven shal't,-asthis shat't runs too slowly to obtain an etl'eetive lubrication. Forthis reason 1 simply use a paeking box 84. for said shat't, said boxbeing preferably so arranged as to permit re-paeking without dismantlingthe: unit. ()n the rapidly running shaft, however, it is not suitable touse. a packing box, and this is also unneeessary as an etleetive.splashing aetion ean be obtained on aeeount ot the high velocity ofrotation of said shaft.

As already stated, the. partition wall 63 divides the gear easing int-otwo eompartments, one (85) containing the rapidly runniug yieldable gearwheels aml another (8(3) containing the slower running gear wheels. ()ilsupplied to the last-mentioned eompartment 86 passes an over-[low 87(see Fig. t) 'in the partition wall (33 into the first compartment 85.The tilling of the. outer eompartment 86 is so adapted as to attain acertain oil level in the latter eom airtment 85 whieh may be controlledby means of an oil stand pipe or the like (uotshowu). In sueh manner twodilterent oil levels are obtained which may. be adjusted in the bestpossible manner. As will be described in the following when dealing withthe lubrication of the. gear, oil is splashed up by the .yieldable. gearwheels 5%) into'sumps arranged above the seeondary pinions (34 andprovided with holes at their bottom, the. oil thence. flowing down intothe. compartment Ht tor the slowest running wheels, whilst lulnieatingsaid wheels. 'It has shown in praetiee that the difference in levelbetween the two eompartmeuts is not equalized during operation.

The oil packing means between the gear part and the eleeti'ie part of myunit is espeeially clear from Fig. '10 and Fig 4. .\rranged behind theball bearing :25 ot' the driving shaft 23 is a stationary plate 8hpreventing the greater part of the oil from passing through the bearing.The plate is provided with an annular opening adjacent an oil ejector89. The oil passing through the bearing is forced by the oil ejector 89into an annular space 90 in the bearing box 5 33, said oil ejector beingprovided with a lip 91 so as to cause oil having entered said space torun down into the lower part of the bearing box. At this place holes andchannels 92 are provided so as to cause the oil to be drained back tothe gear (see Fig. It is of importance that the return hole or channelopens below the normal oil level in the gear casing, as otherwise, ifthe return hole is arranged above said level, the rapidly rotatingyieldable gear wheels 59 may force the oil upwardly into said hole andup to the oil packing means, thus obtaining a result contrary to thatdesired.

Between the lip 91 in the bearing box 33 and the oil ejector 89 there isa little play which must be very small as'otherwise the oil will creepalong the stationary bearing box, thus causing leakage. If on thecontrary said play is small this oil stream will be caught by the oilejector and returned into the bearing box. As it' is diflicult to keepall axial measures with sufliciently small tolerance a readjustment inmounting will be necessary. On mounting, the bearing box 33 is adjustedinto its correct position and'then the distance between the guiding pin93 screwed into the box 33 and the end wall 57 of the casing iscarefully ascertained. Thereafter the same distance is measured onthetop half 10 of the casing and a hole 94 is bored into the partitionwall 26 of "said half at said distance from the end wall, so that, whenthe top half is laid down on the bottom half 11, the guiding pin 93engages said hole 94, thus fixing the bearing box in all direction v (d)The oil relay The unit is protected against dangerous overload currentsby fuses'or automatic controlling-means and, consequently, the gear partof the unit cannot be subjected to any continuous overload resulting ininjury of the teeth. However, th'e gear will be ruined rapidly, ifsufiicient oil is not at hand for lubrication. An oil controlling devicefor the gear must operate very quickly, that is before any undue wearhas occurred. For this purpose, my improved unit is provided with an oilrelay preventing any damage of the gear. The relay is especially shownin Figs. 7 and 11.

Formed on the top half 10 in the compartment 85 in which the yieldablegear wheels 59 run and above the driving pinion 58 is an oil cup 95 intowhich oil is splashed up by one of the rapidly rotating yieldable gearwheels 59. Formed on the top half above each of the pinions 64 of theintermediate shaft 60 is anoil sump 96 or the like communicating withthe oil cup 95 by means of a groove 97 formed in the partition wall 63.The cup 95 as well as the sump 96 facilitate the reinforcing of the gearpart of the casing. At the bottom of the sumps 96 are holes 98, thetotal area of which is so adapted as to cause oil to collect in thesumps to a certain level. Any superfluous oil may run off over the edgesof the sumps. Arranged in one of the sumps is a float 99 of electricallyconducting material, for instance brass, provided with two recesses 100and extending into each of said recesses is a pin 101 fixed to aconnection box 102 and insulated as at 103 from same, said box beingfixed to the casing 10. A spring 104 coiled around each of the pins 101is at its upperend secured to the pin and bears at its lower end againstmetal contacts 105 fixed to the float 99, silver being preferably usedas material for said contacts. A double cable 106 extends from the topend of the pins 101 to the terminal plate 31 of the rotor from where theone conductor of the cable 106 extends to one of the two controlcontacts in the collector-ring device, ,whereas the other con-' ductorextends to the motor switch box, this arrangement being more fullydescribed in the following.

As long as the compartment 85 of the casing in which the yieldable gearwheels rotate contains oil suflicient to fill the cup 95 bysplashingaction the sump 96 in which the float 99 is arranged willcontain such a quantity of oil flowing in through groove 97 that thefloat 99 ascends to such a level as to ensure electric contact betweenthe pins 101 by means of the contacts 105 of the (6). The collector-ringale vice As stated above, the cables 30 and 35 for the stator and rotorwindings, respectively, are conducted to the electric part of the motorfrom terminal plates 31 and cable boxes 32 and 36, the three cables 30for the stator windings being directly connected with same, whereas thethree cables 35 for the rotor windings are led to the collectorringdevice shown especially in Figs. 3 and 6. The three rotor cables are inknown manner each led to a terminal 37 (one being shown in Fig. 6) fixedto a supporting member 107 secured to a square shaft 108, two suchshafts being provided each carrying three brush holders 38 of the threepairs of such holders. The brush holders 38 are each pivotally mountedon the respective supporting member 107 as at 109, said member beingconnected with the holder 38 by means of a spring 110 tending tomaintain the brush 111 of the holder in contact with the correspondingcollector-ring 39. These collector-rings 39 are insulated from eachother as at 112 and are each electrically connected with a screwterminal 113. A cable 40 leads from each of said screws 113 through thebore 41 in the driving shaft 23 to the rotor windings 22, as statedabove.

The shafts 108 are each journalled at one end in the bearing shield 16and fixed to each of the shafts 108 is the one end of a helical spring114; coiled around the shaft 108 and terminating at its other end in anarm 115 resting against the bearing shield 16. The brush holders 38 areelectrically connected in pairs by means of a V-shaped spring 116.

The short-circuit means of the collectorring device comprises ashort-circuit ring 117 slidingly mounted on the driving shaft 23 andshort-circuit contacts 118 and 119, two for each pairs of brushes. Thesecontacts are placed axially and the one 118 is formed as a stirrup,whereas the other contact 119 has the form of a knife permitting goodresiliencyin the contact. The short-circuit ring 117 is operated by amanoeuvring shaft 120 provided with a handle 121 and engaging by a stud122 a groove in said ring with a certain play. The manoeuvring shaft 120is journalled in the upper wall of the shield 16 and in a projection 123on said shield. Fixed on said shaft 120 are two cam disks 124 and 125arranged cccentrically on the shaft. Abutting against said disks arearms 126 and 127 secured to the shafts 108. On account of the action ofthe helical springs 114 said arms 126 and 127 will rest with a certainpressure against the cam disks 124 and 125, thus preventing themanoeuvring shaft 120 from unintentional rotation during running withfollowing friction against the groove in the short circuit-ring 117 andcorresponding wear.

When operated the manoeuvring shaft 120 is turned through somewhat morethan 180 so that the contact between the stud 122 and the groove in thering 117 necessary for the displacement of the latter ceases, thuspreventing Wear of these parts.

The collector-rin device is provided with means for preventing the rotorfrom being short-circuited, before the motor-starter is short-circuited.This means comprises two contacts 128 connected by cables 129 in serieswith an under-voltage release in the motor switch box. A pin 130 on themanoeuvring shaft 120 short-circuits said contacts 128 when said shaftis in starting position. Consequently, the motor switch box can only beoperated when this circuit is closed. When the collector-ring device isshort-circuited this circuit will, of course, be broken, but at saidmoment the whole contact device is shunted at the 1notor-starter.

VI. Tim ELEUI'RIC, CONNECTIONS The electric connections of the unit areshown diagrannuatically'in Fig. 12, the motor shown being of thethree-phase. type. In this figure reference chariu-ter A designates themotor, B the starter and C the switch box controlling device. .lllectriccurrent is supplied through the three conduits L, Z- I over contacts inthe motor controlling device. con'iprising three main contacts a (1..(a, and three. auxiliary contacts 2),, 71 1):, and over two overloadrelays 9a,, m, arranged in two of the conduits Z,, l. leading to thestator terminal box. In operation the contacts 7),, b are closed alittle earlier than the other contacts in the switch box for the purposeto be described in the following. The motor controller U comprises anunder-voltage release consisting of an" electro-magnet c with anarmature (Z pivotally mounted as at c and actuated by a spring f tendingto keep the armature. in unattracted position. The armature (Z isfork-shaped and cooperates with a rod g on which all the knives of thecontacts (1,, a. a and b,, 2) b are secured. At its end the rod 9 isprovided with a hook a co-opcrating with a hook it at the end or one ofthe fork shanks. The rod {1 is provided with an operating handle it. Aspring ll: keeps the rod'g in position out of engagement with thefork-shaped armature d.

The rotor cable box has six terminals, three main contacts 0 0 ,0, andthree contacts 7),, 1):, p for auxiliary conduits. q designates the oilrelay, 7' the control contacts designated in Fig. 6 by 128, a thecollector-ring device and t a contact operated by, for instance, apress-button v".

The motor-starter B consists in known manner of rheostats w co-operatingwith a movable control arm :1) which can be moved along the rheostats inorderto vary the resistance. This arm cooperates with two contacts 3 and2.

When the motor is to be started the control contacts 7 (128) are firstclosed by rotating the manoeuvring handle 121 (see Fig. 6) resulting inthe brushes 111 of the collector-ring device being brought in contact'with the. collector-rings 39. Then the. operating handle it is turnedin counterclockwise direction as shown in Fi 12 resulting in thecontacts 6 and b being first closed so that an electric circuit isestablished from conduit 7,, through the electromagnet c of theundervoltage relay, overload relays 911,, m contact 1),, on the rotorcable box, control contact 1', contact on the rotor cable box, contact 2of the motorstarter, contact b5 in the motor controlling device andconduit Z Thereby the electromagn'et c is excited attracting itsarmature (Z against the action of the spring f, whereby ,the operatinghandle h canbe turned further,

until all contacts in'the inotor controlling device are closed. Shouldthe control contact 1' not be closed before actuating the motorcorgtrolling device, the rod can be displaced -only through such adistance that contacts b vand 7; are closed, this on account of the rodabutting against the fork shank In such case the circuit above referredto is broken at the control contact 1"- so that the armature d, is notattracted. Then the stator gets current and the motorstarter B isactuated putting the resistances w gradually out of circuit. As soon asthe motor-starter is actuated, the electric circuit above referred towould be broken at contact--z resulting in the armature (Z fall; ingdown and breaking the circuit of,the stator, if no means were providedfor preventing this result. Such means consists in the pness-button'o bywhich the contact If is closed, before the motor-starteris ace tuated.The circuit through the undervolt:

age relay is by this means maintained over said contact t, contact b -mthe motor concable box, oil relay 9, contact p of the rotor cable box,contactb of the motor controlling device and conduit Z When themotor-starterhas been short-circuited,- the rotor is short-circuited,over the motorstarter. By returning tlie manoeuvring handle 121 into itsoriginal position, the

brushes 111 are lifted from the collectorrings 39 and the controlcontact 1 is broken, thus short-circuiting the rotor within the motor,this latter operation being not inevitably necessary, as the controlcontact 1" does not establish any electric circuit at this stage. Bylifting the brushes from contact with the collector-rings in thismanner, th brushes are protected against wear. I

hen the contact of the oil relay ,isbroken VII. OrHERGHARAorERIs'rrcs orMY IMPROVED UNrr -'As stated above the stator and the, rotor can beremoved from the casing Without it being necessary to remove the casingfrom its .bed or foundation. For this purpose the top half 10 of thecasing together with the upper part of the bearing shield 16 areunscrewed and removed, after the casing 17 of thecollector-ring devicehaving been loosened and removed. Then the bearing races 68 and 69of theintermediate shafts 60 are removed whereupon said shafts are displacedlaterally so as to bring their toothed wheels 59 out of engagement withthe driving pinion 58. Now the tator 21 with itscage 27 and end covers50, the rotor 22, the driving shaft 23, the, bearing box and the drivingpinion 58 as well as the collector-ring device can be lifted out fromthe bottom casing half 11. If the end covers and rthe bottom part of theend' shield 16 are removed and also the fan 42 is unscrewed from its hub43 by loosening the screws 44 the. rotor together with the partsconnected therewith may bedrawn out axially of. the casing and then thestator with its cage 27 may be lifted but.

In order to facilitate the mounting of the top casing 10 onto 'thebottom casingll the former isprovided with a plurality of guiding pins131 to be brought into engagement with corresponding holes in the bottomcasing 11.

In addition to the screw bolts 13 and nuts 14 connecting the two halvestogether head screws 1 32 may be provided to be screwed through holes inthe top casing 10 into corresponding threaded holes'133 in the bottomcasing 11. A

It is evident that byadapting' the diameters ofthe gear wheelsof thegear any de-' sired transmission ratio maybe obtained between thevdrlvmg' and the driven shaft and thatit is also possible to use morethan one intermediate shaft at each side of said shafts in order tofurther decrease said ratio.

' Figs. 13 and 1'4 showan embodiment of the arrangement for bringing thegear wheels of the intermediate shafts out, of en gagement with the gearwheels of the driving and driven shafts if the bearings journallfng theintermediate shafts are mounted .in undivided races.- Fig. 13 shows aside -v1ew of one of the bearings of the intermediate shafts and Fig. 11 a central section therethrough. Reference character 60 designates theintermediate shaft, 134 the bearing and'135 the undivided race, \Vith 10is in the manner above described the circuit d i n t d th t t d ith 11th b tof the undervoltage relay is broken, result" ing in all contactsof the motor controlling 65 device being broken and the iotor stopped.

tom-part of the gear casing. The race 135 is provided with recesses 136extending peripherally over apart of the race and formed with a centralprojection In the bottom part 11 of thegear cas ng there is a peripheralgroove 138 corresponding to the projection 137 and located on theopposite side of the driven and driving shafts. A pm 139 engages therace and the parts 1t) and 11 of the casing for preventing rotation ofthe race.

\Vhen dismantling the gear the upperpart 10 of the casing is removed.Afterthe pin 139 has been removed the race 16:) is turned until theprojectioirlii'i' faces the groove 138. Then it is possible toLlISPlZICS- the shaft laterally in that the PI'OJGCUOH 13 enters intothe groove 138 and tihe gear wheels (59, 5S and (ii, 65, see Fig. a) arebrought out of engagement w th each other so that the shaft (30 can belifted. By inserting a rod or the like in a hole 149 of the race 135 theturning of same is facilitated. The race is supported around its wholeperiphery when mounted in the casing as shown in the figures by thePlOjOCt-IOII bearing against the casing. \Vhen under load thus nodeflection of the race can occur.

The invention is not limited to'the embodiments shown but may be variedin several respects without departing from its scope.

I claim: i

1. A geared electric motor unit COIHPIIS: ing an electric motor, a gear,a casing common to said electric motor and said gear and dividedlongitudinally into two halves detachably connected w th each other, at'ansverse partition in said casing d viding same into two compartments,one for the electric motor and one for the gear, a driving shaft for theelectric motor, a bearing for said shaft arranged in said partition, abox for said bearing having an annular space and means to return 011leaking through said bearing nto said annular space from said space backinto the gear compartment.

2. A geared electric motor unit comprising an electric motor, a gear, a-as1ng common to said electric motor and said gear and dividedlongitudinally into two halves detachably connected with each other, atransverse partition in said casing dividing same into two compartments,one for the electric motor and the other for the gear, a transverse wallin said gear compartment dividing same into two chambers, and means tocirculate oil from the lower port on or the inner chamber to the upperportion of the outer chamber.

A geared electric motor unit compris ing an electric motor, a gear, acasing coniiuon to said electric motor and said gear and dividedlongitudinally into two halves detachably connected with each other, atransverse partition in said casing d viding same into two compartments,one for the electric motor and the other for thegear, a transverse wallin said gear compartment dividing same into two chambers, the lowerparts of said chambers being formed as oil reservoirs, an-oil cup in theupper part of the inner chamber, an oil sump in the upper part ofthe'outer chamber communicating with said oil cup and provided withbottom holes and an over-flow in said wall.

4. A geared electric motor unit comprising an electric motor, a gear, acasing surrounding said clectric motor and said gear and dividedlongitudinally into two halves detachably connected withv each other, atransverse partition in said casing separating the electric motor andthe gear, a transverse wall in the gear compartment dividing same intotwo chambers, the lower parts of said chambers being formed as oilreservoirs, means to circulate oil from the one chamber to the otherrandan electric circuit including a float and an electric part and adaptedto be broken by said float upon an insullicient quantity of lubricantbeing circulated. i

5. In a device of the character described, a casing longitudinallydivided into an upper and a lower part, a transverse partition in eachof said parts dividing said casing into a motor chamber and a gearchamber, an electric motor in said motor chamber, a shaft for said motorjournalled in said partition and extending into said gear chamber, anintermediate transverse wall in said gear chamber, a driven shaft and aplurality of intermediate shafts join-nailed in an outside wall of saidcasing and in said intermediate wall, and intermeshing gears mounted onsaid motor shaft and said intermediate shafts and on said intermediateshafts and said driven shafts.

6. In a device of the character described, a casing longitudinallydivided into an upper and a lower part, a transverse partition in eachof said parts dividing said casing into a motor chamber and a gearchamber, an electric motor in said motor chamber, a shaft for said motorjournalled in said partition and extending into said gear chamber, anintermediate transverse wall in said gear chamber, a driven shaft and aplurality of' intermediate shafts join-nailed in an outside wall of saidcasing and in said intermediate wall, a gear mounted on each of saidintermediate shafts betwecn said partition and said intermediate wall, apinion on said motor shaft meshing with said gears, and intermeshinggears mounted on said intermediate shafts and said driven shaft.

7. In a-devicc of the .character described, a casing longitudinallydivided into an upper and a lower part, a transverse partition in eachof said parts dividing said casing into a motor chamber and a gearchan'iber, an electric motor in said motor chamber, a

shaft for said motor journalled in said partition and extending intosaid gear chamber, an intermediate transverse wall in said gear chamber,a driven shaft and a plurality of intermediate shafts journalled in anoutside wall of said casing and in said intermediate Wall, a yieldablegear mounted on each of said intermediate shafts between said partitioand said intermediate wall, a pinion on s id motor shaft meshing withsaid yieldable gears, and intermeshing gears mounted on saidintermediate shafts and said driven shaft.

8. In a device of the character described, a casing longitudinallydivided into an upper and a lower part, a transverse partition in eachof said parts dividing said easing into a motor chamber and a gearchamber, an electric motor in said motor chamber, a shaft for said motorjournalled in said partition and extending into said gear chamber, anintermediate transverse wall in said gear chamber, a driven shaft and aplurality of intermediate shafts ,journalled in an outside wall of saidcasing and in said intermediate wall, a gear mounted on said drivenshaft between said outside wall and said intermediate wall, gears onsaid intermediate" tition and extending into said gear cham-' her, anintermediate transverse wall in said gear chamber, a driven shaft and aplurality of intermediate shafts journalled in an outside wall of saidcasing and in said intermediate wall, a gear mounted on each,

of said intermediate shafts between said outside wall and saidintermediate wall, a

a gear on said driven shaft meshing with said gears, and intermeshinggears mounted on said intermediate shafts and said motor shaft.

10. In a device of the character described, a casing longitudinallydivided into an upper and a lower part, a transverse partitionin each ofsaid parts dividing said easing into a motor chamber and a gear chamber,an electric motor in said motor chamber, a shaft for said motorjournalled in said partition and extending into said gear chamher,- anintermediate transverse wall in said gear chamber, ;a driven shaft and aplurality of intermediate shafts each journalled in an,outside wall ofsaid casing and in said intermediate wall, said intermediate shaftsprojecting through said intermediate wall and said driven shaft being inaxial alignment with the motor shaft, a pinion mounted in overhungrelation on the end of the motor shaft, a gear mounted in overhunrelation on each of said intermediate sha' ts between said partition andsaid intermediate wall said gears meshing with said pinion, a drif engear mounted on the driven shaft between the outside wall of the casingin which the shaft is journalled and said intermediate wall and gearsmeshing with said driven gear and mounted on said intermediate shaftsbetween the outside wall ofthe casing in which said shafts arejournalled and saidintermediate wall.

In testimony whereof I affix my signature.

WILHELM ROBERT UGGLA.

